1. Field of the Invention
The present invention relates to a flow chamber and an electro-manipulator incorporating the same which enables continuous flow electro-fusion or electro-transfection.
2. Description of the Prior Art
Electro-fusion which was developed and established by Zimmermann et al in 1981 relies on the following principle. A cell suspension is introduced into a space between the electrodes disposed in parallel. When an alternating current is applied between the electrodes, the cells are moved in an electric field in the direction of the highest field strength and are oriented into a configuration resembling of a pearl chain. Application of direct-current pulses having a duration ranging between several .mu.s to several tens of .mu.s to the cells in this state induces reversible disorder of the lipid bilayers constituting the cell membranes and reassembly thereof, which leads to fusion of the cells (Angew. Chem. Int. Ed Engl. 20. 325-344, 1981; PHYSIOL. PLANT. 67:50 7-516. Copenhagan 1986).
Electro-transfection is a technique developed in 1982 by Neumann et al. This involves the introduction of a mixture of cells and nucleic acids between the electrodes and application of direct-current pulses having a duration ranging between several .mu.s to several tens of .mu.s between the electrodes which causes introduction (transfection) of the nucleic acids into the cells.
The present inventors have developed a chamber which includes a flat-sided spacer having a notch and a pair of gold evaporated glass panel electrodes separated by the spacer, and the use of this chamber has made it possible for them to increase the cell fusion rate and nucleic acid transfection rate up to 96% and 95%, respectively (J. Gen. Virol., 1986, 67, 2037-2042).
Known chambers, however, require manual replacement of samples used for electro-fusion or electro-transfection. With such chamber, therefore, it has been impossible to process a large number of cells in a short period of time. In addition, the known chambers require a complicated series of operations.